I saw litle about this in the message of OddBall. But i don't understand exaclty. Whats the diference of two heads? Is the camshafts(with more duration), or is the dutes of head have more diameter?
I have the C20XE head here in my house, is from Vectra CD 2.0 16V(here in Brazil this car have 135hp), and i would like know if i need put much money for find the same efficience of the head of 150/156hp...